Shock-absorber pistons are known which have a circumferential chamber on both faces of the piston body, each chamber being provided with a valve spring disk which is centrally clamped, and which rests at its periphery on a circumferential shoulder around the circumferential chamber.
Such known piston bodies moreover have two groups of counterflow fluid transit channels, each channel going from one circumferential chamber obliquely through the piston body to the opposite face of the piston body, and exiting there outside the circumferential shoulder.
Shock-absorber pistons of this type are described for example in German Pat. No. 969 330. By virtue of having circumferential chambers on both faces, the centrally-clamped valve spring disks which cover them become quite loaded hydraulically across their entire surface when the piston is moved in either direction, thus on either the push or pull stroke. This situation requires the use of rather thick valve spring disks or sets of such disks.
Moreover, it has been found desirable to minimize the disturbing noise of shock impact by having relatively small contact of the periphery of the valve spring disk with the circumferential shoulder surrounding the circumferential chamber.
In the prior art shock-absorber pistons, the hydraulic flow incident to the valve spring disks has still been unsatisfactory despite impaction by way of the associated circumferential chamber, because the transit channels leading to the circumferential chamber have generally been of narrow cross-section, which, especially in the case of high piston speeds, often results in high power requirements for the shock-absorbing action.
This problem is further intensified where the entrance apertures of the prior art shock-absorber pistons are also constricted, and where the pistons also have valve spring disks with outer flanges which move forward axially to a substantial extent.
Such valve spring disks are those which are positionable on the shaft and held by a lock nut. Such prior art shock-absorber pistons have a persistent and prevalant characteristic, which exerts an adverse effect on driving safety; in the range of higher piston speeds, on account cf the excessively strong braking of the piston motion, the ability of the vehicle wheels to adhere to the road is substantially reduced.